This invention concerns a method to apply bends in the trailing end of sections in an automatic or non-automatic bending-shaping machine by a bending unit positioned downstream of a unit that feeds sections.
A machine to which the invention is applied is disclosed in IT-A-15904 A/89 (EP-A-379043).
The bending-shaping machines to which the invention is applied have the purpose advantageously, but not only, of producing straight reinforcement bars including one or more bends in both ends of these bars. The machines can also have the purpose of bending hollow or solid sections of any type at both ends with bends having a clockwise and/or anticlockwise development.
The sections which can be bent with the bending-shaping machines to which this invention is applied may be pre-straightened, pre-straightened and sheared to size or unwound from rolls.
Document IT-A-15904 A/89 (EP-A-379043) discloses a bending-shaping machine with a bending unit, the machine feeding the sections continuously and being suitable to make the desired bends automatically in both ends of a section sheared to size.
This machine can make the bends in both ends of the section, but the making of clockwise and anticlockwise bends in the trailing end is effected with the same system as that employed for bends in the leading end, that is to say, when the bends are to be changed from clockwise bends to anticlockwise bends and viceversa, the bending unit is lowered and caused to pass beneath the section so as to be positioned on the other side of the section.
This system in itself is excellent but entails a great drawback as regards the times of the cycle required for this displacement; these times are deemed to be too long.